The present invention relates generally to compositions comprising a potentiator such as IL-18, also known as interferon-xcex3-inducing factor (IGIF), and chemotherapeutic agents. The chemotherapeutic agents may be, for example, camptothecins such as topotecan, anthracycline antibiotics such as doxorubicin, alkylating agents such as cyclophosphamide, or antimicrotubule agents such as paclitaxel. The present invention further relates to processes for making such compositions, the use of such compositions for the prevention and/or treatment of cancer, and the use of such compositions to inhibit the growth of tumors or cancerous cells in mammals.
There have been significant advances in understanding the genetic and cellular changes that lead to cancer and that result in progression to more malignant and metastatic disease. There has been less impressive advances in therapy of metastatic cancer as many of the high-incidence tumors, such as colon, lung, prostate and breast cancer, either respond briefly or fail to respond at all to even the newest regimens of chemotherapeutic agents. The molecular biological studies of cancer have provided an understanding of the reasons why tumors fail to respond to chemotherapy. In normal cells, induction of DNA damage or other metabolic insult by chemotherapeutic agents turns on a programmed cell death pathway (apoptosis). As part of the genetic evolution of tumors, there is an upregulation of pathways that prevent apoptosis. This occurs as the result of selection for mutations, such as loss of p53 function or overexpression of bc1-2, that promote survival, since the aberrant DNA replication that occurs in cancer cells normally would trigger apoptosis. The fact that anti-apoptotic pathways are activated in tumor cells suggests that these cells will be refractory to many different chemotherapeutic agents, regardless of mechanism. Thus, it will be important to introduce new therapeutic modalities, such as inhibition of tumor-induced angiogenesis or stimulation of the immune response to tumors, to produce responses in chemorefractory cancers.
IL-18, also known as interferon-xcex3-inducing factor (IGIF), is a recently discovered novel cytokine. Active IL-18 contains 157 amino acid residues. It has potent biological activities, including induction of interferon-xcex3-production by T cells and splenocytes, enhancement of the killing activity of NK cells and promotion of the differentiation of naive CD4+T cells into Th1 cells. In addition, human IL-18 augments the production of GM-CSF and decreases the production of IL-10. IL-18 has been shown to have greater interferon-xcex3 inducing capabilities than IL-12, and appears to have different receptors and utilize a distinct signal transduction pathway.
The therapeutic potentials for IL-18 in the treatment of cancer and for its antibody in the treatment of endotoxic shock induced liver damage (which is similar to human hepatic failure), have been evaluated in animal models, and protective effects have been demonstrated. For example, IL-18 has been reported to inhibit the metastasis and growth of colon 26 adenocarcinoma in mice. See, Hanaya, et al., Anti-tumor effect of a new cytokine, IGIF on the metastasis and growth of murine colon 26 adenocarcinoma. Proceeding of the American Association for Cancer Research 37: 451-452 (1996). Further studies regarding the anti-tumor activity of IL-18 have been reported in the following publications: Micallef et al., Interleukin 18 induces the sequential activation of natural killer cells and cytotoxic T Lymphocytes to protect syngeneic mice from transplantation with Meth A sarcoma, Cancer Res. 57:4557-4563 (1997); Yoshida et al., Antitumor effect of human pancreatic cancer cells transduced with cytokine genes which activate Th1 helper T cells, Anticancer Res. 18:333-336, (1998); Osaki et al., IFN-xcex3-inducing factor/IL-18 administration mediates IFN-xcex3- and IL-12-independent antitumor effects, J. Immunol. 160:1742-1749 (1998); and Micallef et al., Augmentation of in vitro interleukin 10 production after in vivo administration of interleukin 18 is activated macrophage-dependent and is probably not involved in the antitumor effects of interleukin 18, Anticancer Res. 18(6A):4267-74 (1998).
CD4+T cells are the central regulatory elements of all immune responses. They are divided into two subsets, Th1 and Th2. Each subset is defined by its ability to secrete different cytokines. Interestingly, the most potent inducers for the differentiation are cytokines themselves. The development of Th2 cells from naive precursors is induced by IL4. Prior to the discovery of IL-18, IL-12 was thought of as the principal Th1 inducing cytokine. IL-18 is also a Th1 inducing cytokine and is more potent than IL-12 in stimulating the production of interferon-xcex3.
Th1 cells secrete IL-2, interferon-xcex3, and TNF-xcex2. Interferon-xcex3, the signature Th1 cytokine, acts directly on macrophages to enhance their microbiocidal and phagocytic activities. As a result, the activated macrophages can efficiently destroy intracellular pathogens and tumor cells. The Th2 cells produce IL-4, IL-5, IL-6, IL-10 and IL-13, which act by helping B cells develop into antibody-producing cells. Taken together, Th1 cells are primarily responsible for cell-mediated immunity, while Th2 cells are responsible for humoral immunity
IL-18, the encoding nucleotide sequence, and certain physicochemical chemical properties of the purified protein is known.
Kabushiki Kaisha Hayashibara Seibutsu Kayaku Kenkyujo""s (xe2x80x9cHayashibaraxe2x80x9d), EP 0692536 A2, published on Jan. 17, 1996, discloses a mouse protein which induces IFN-gamma production by immunocompetent cells, the protein being further characterized as having certain physicochemical properties and a defined partial amino acid sequence. Also disclosed is a protein having a 157 aa sequence, two fragments thereof, DNA (471 bp) encoding the protein, hybridomas, protein purification methods, and methods for detecting the protein.
Hayashibara""s EP 0712931 A2, published on May 22, 1996, discloses a 157 aa human protein and homologues thereof, DNA encoding the protein, transformants, processes for preparing the protein, monoclonal antibodies against the protein, hybridomas, protein purification methods, and methods for detecting the protein.
Hayashibara""s EP 0767178 A1, published on Apr. 9, 1997, discloses a human protein having a 10 aa sequence near the N-terminus and which induces the interferon gamma production by an immunocompetent cell. Also disclosed are processes for producing the protein, the protein as a pharmaceutical agent, use of the protein as an antioncotic agent, antitumor agent, antiviral agent, antibacterial agent, immunopathy agent and for treatment of atopic diseases.
Incyte Pharmaceuticals, Inc.""s, WO 97/24441, published on Jul. 10, 1997, discloses a 193 aa protein corresponding to IL-18 precursor and encoding DNA.
Chemotherapeutic agents are known in the art. For example, camptothecins, including topotecan, are disclosed in SmithKline Beecham Corporation""s, U.S. Pat. No. 5,004,758 (758 patent), issued on Apr. 2, 1991. Camptothecins, including topotecan, are also disclosed in Cancer Chemotherapy and Biotherapy, second edition, edited by Bruce A. Chabner and Dan L. Longo, Lippincott-Raven Publishers, Philadelphia (copyright) 1996. pp. 463-484. Topotecan is disclosed in The Merck Index, Twelfth Edition, (copyright) 1996 Merck and Co., Inc. under monograph number 9687. Anthracycline antibiotics, including doxorubicin, are disclosed in Cancer Chemotherapy and Biotherapy, second edition, edited by Bruce A. Chabner and Dan L. Longo, Lippincott-Raven Publishers, Philadelphia (copyright) 1996. pp. 409-434. Doxorubicin is disclosed in The Merck Index, Twelfth Edition, (copyright) 1996 Merck and Co., Inc. under monograph number 3495. Alkylating agents, including cyclophosphamide, are disclosed in Cancer Chemotherapy and Biotherapy, second edition, edited by Bruce A. Chabner and Dan L. Longo, Lippincott-Raven Publishers, Philadelphia (copyright) 1996. pp. 297-332. Cyclophosphamide is disclosed in The Merck Index, Twelfth Edition, (copyright) 1996 Merck and Co., Inc. under monograph number 2816. Antimicrotubule agents, including paclitaxel, are disclosed in Cancer Chemotherapy and Biotherapy, second edition, edited by Bruce A. Chabner and Dan L. Longo, Lippincott-Raven Publishers, Philadelphia (copyright) 1996. pp. 263-296. Paclitaxel is disclosed in The Merck Index, Twelfth Edition, (copyright) 1996 Merck and Co., Inc. under monograph number 7117. Other chemotherapeutic agents are known to those skilled in the art.
In one aspect, the present invention provides a polypeptide having at least 70% identity of the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:2 over the entire length of the sequences in combination with a chemotherapeutic agent.
In another aspect, the present invention provides a polypeptide having at least 70% identity of the amino acid sequence of SEQ ID NO:1 or SEQ ID NO:2 over the entire length of the sequences in combination with a chemotherapeutic agent including, preferably, a camptothecin, such as topotecan, an anthracycline antibiotic, such as doxorubicin, an alkylating agent such as cyclophosphamide, or an antimicrotubule agent such as paclitaxel. More preferably, the chemotherapeutic agent is topoisomerase. Most preferably, the chemotherapeutic agent is topotecan. Combinations of the polypeptide with other chemotherapeutic agents known to those skilled in the art are also encompassed by this invention.
In yet another aspect, the present invention provides a pharmaceutical composition comprising a polypeptide, such as IL-18, a chemotherapeutic agent, and a pharmaceutically acceptable carrier.
In a further aspect, the present invention provides a process for preparing the composition described above comprising combining the polypeptide with the chemotherapeutic agent and recovering the resulting composition.
In a further aspect, the present invention provides a method of preventing and/or treating cancer in a mammal comprising the administration of a cancer inhibiting amount of a composition comprising a polypeptide, such as IL-18, and a chemotherapeutic agent.
In a further aspect, the present invention provides a method of preventing and/or treating cancer in a mammal comprising the administration of a cancer inhibiting amount of a composition comprising a polypeptide, such as IL-18, and a chemotherapeutic agent, and a pharmaceutically acceptable carrier.
In another aspect, the present invention provides a method of inhibiting the growth of tumor cells in a mammal sensitive to a composition comprising a polypeptide, such as IL-18, and a chemotherapeutic agent, wherein such method comprises administering to a mammal afflicted with said tumor cells, an effective, tumor cell growth inhibiting amount of such composition.
In another aspect, the present invention provides a method of inhibiting the growth of tumor cells in a mammal sensitive to a composition comprising a polypeptide, such as IL-18, and a chemotherapeutic agent, and a pharmaceutically acceptable carrier, wherein such method comprises administering to a mammal afflicted with said tumor cells, an effective, tumor cell growth inhibiting amount of such composition.